1. Field of the Invention
This invention relates generally to record players, and more particularly is directed to a record player having an improved record turn-over mechanism by which a phonograph or other record disc can be turned-over or inverted after the playing of one side so as to permit the reproduction or playback of signals recorded on both sides or surfaces of the record disc.
2. Description of the Prior Art
Record players of the so called "turn-over" type are already known, for example, as disclosed in detail in U.S. Pat. Nos. 2,601,301, 2,735,683 and 3,275,327. In the record players disclosed in the first two enumerated patents, there is provided a vacuum-grip turntable adapted to grip a record disc by vacuum only at the central ungrooved portion of the disc so as to expose the playing grooves on both sides of the record. Such vacuum-grip turntable is carried by a turntable cradle which is swingable between an upright position in which the turntable faces upward, and an inverted position in which the turntable faces downward. The record player further includes a pivoted record transfer arm carrying a vacuum-grip record lifter and being movable between a position extending over a platform adapted to receive a supply stack of records and a position extending over the turntable in the upright position of the latter. In operating the foregoing record player of the turn-over type, the record transfer arm initially swings over the platform so that the record lifter engages the central portion of the uppermost record in the stack thereon and is evacuated to grip the engaged record. The transfer arm then swings away from the stack and transfers the gripped record to a centered position on the upright turntable. The vacuum grip of the record lifter is released and the record is thereupon gripped and rotated by the turntable. At the conclusion of the playing of the first side of the record, the turntable is inverted to similarly invert the record and the other or second side of the record is played or reproduced. At the conclusion of the playing of the second side of the record, the vacuum grip of the inverted turntable is released, and the record drops therefrom into an underlying record receiver. The foregoing record player of the turn-over type is disadvantageously complex in that it requires devices for the controlled application of vacuum to both the vacuum-grip turntable and the vacuum-grip record lifter, and also in that the turntable has to be mounted, as in the mentioned swingable cradle, for bodily movements between upright and inverted positions. Further, since the turntable continuously grips the record at a side of the latter during the playing of first one side and then the other side of the record, the turntable can only engage the record at the central ungrooved portion of the record so as to expose the playing grooves on both sides thereof.
In U.S. Pat. No. 3,275,327, there is disclosed an improvement over the previously described record player of the turn-over type in which the inverted turntable is carried by the transfer arm and serves as both a record lifter and a turntable, thereby eliminating the necessity for a separate vacuum-grip record lifter. Thus, in the record player of U.S. Pat. No. 3,275,327, the transfer arm is in the form of a pivotally mounted yoke on which the turntable cradle is, in turn, pivotally mounted. In operation of such record player, the yoke and cradle are initially positioned to bring the inverted vacuum-grip turntable down on the uppermost record in a supply stack, so as to grip such uppermost record. The yoke is then swung away from the supply stack to a playing position with the turntable remaining inverted, and a turntable drive wheel then comes into engagement with the rim of a fly wheel rotatably coupled with the turntable so as to drive the latter in the proper direction for playing the record. At the conclusion of the playing of the first side of the record, the yoke swings to a transition position and the turntable cradle is rotated to bring the turntable with the record thereon to an upright position, whereupon the yoke is returned to the playing position and a second turntable driving wheel moves into engagement with the fly wheel for driving the turntable in the proper direction for the playing of the second side.
It will be apparent that the last described record player of the turn-over type still necessarily includes a vacuum-grip turntable engageable with each record only at the relatively small area of the central ungrooved portion of the record so that a major portion of the record remains unsupported during the playing or reproducing of the recorded signals. Such limited support of the record during the reproducing or playback operation and the necessity of bodily moving the turntable for inverting the same make it practically impossible to obtain high fidelity sound reproduction in that a relatively large degree of wow and flutter are encountered. Further, relatively large forces need to be exerted for effecting the inverting of the necessarily heavy turntable and associated fly wheel so that a complex actuating mechanism is required.
More recently, it has been proposed to avoid the above-mentioned problems by providing a record player of the turn-over type in which the turntable need not be inverted, but rather is mounted for rotation in a substantially fixed horizontal plane so as to be capable of fully supporting the record disc during the playback or reproducing operation and further to permit the employment of a secure bearing structure for the rotary mounting of the turntable, for example, as disclosed in detail in Japanese Patent Application No. 49-63674, filed June 4, 1974, and which was laid open for public inspection on Dec. 15, 1975, as Japanese Preliminary Publication No. 50-155204. In such record player, the record turn-over mechanism includes splayed record gripping arms having end portions engageable with opposed peripheral portions of a record disc when the arms are flexed toward each other. In addition to being flexibly connected for movement toward and away from each other, the record gripping arms are mounted for turning about an axis which extends midway between the arms in a plane containing the latter, and further the record gripping arms are mounted for swinging of the plane containing the arms about a horizontal axis which is normal to the mentioned turning axis of the arms and disposed to one side of the turntable. In the operation of the record player presently being described, at the completion of the playing of one side of a record disc on the turntable, the record gripping arms are flexed toward each other so as to engage the record disc at its periphery, whereupon the arms are swung upwardly about the horizontal axis which is to one side of the turntable for lifting the gripped record disc from the turntable. Then, the arms and the record disc gripped therebetween are turned through 180.degree. about the turning axis midway between the arms for inverting the record disc and, thereafter, the arms are swung downwardly for returning the inverted disc to the turntable and the arms are flexed away from each other for releasing the record disc on the turntable and thereby permitting the playing of the other side of the disc.
Although the record player with a turn-over mechanism as disclosed in Japanese Patent No. 49-63674 avoids many of the problems associated with record players having a vacuum-grip turntable which is inverted for turning-over the record disc, as earlier described, the turn-over mechanism of the Japanese Patent Application is relatively complex and costly and lacking in reliability particularly in respect to the structures required to effect the various necessary movements of the record gripping arms in the desired timed sequence.